No. 4 is our most responsive mattress. It’s made with 1600 honeycombed pocket springs & 1500 micros springs for the most comfortable nights sleep. We hand fill the mattress with pure new wool & cotton. Then we add Pillow Top – an extra layer that sits on the mattress surface for even more enveloping comfort. It’s filled with the finest natural materials- pashmina, soft bamboo, alpaca, cashmere & silk. Underneath that you’ll find further layers of wool that are all hand-tufted to make sure the mattress keeps its shape over time. It’s finished with Belgian Damask ticking to create a feather-soft surface wherever you lie down. Mattress Tension: One tension.